Just some thoughts on Olivia parentship.
Could Nina be the real Olivia's Mother?
Olivia was treated with cortexiphan and she's blonde, but Bolivia wasn't, and so she's a redhead.
But... if it's true, who the real father is? William Bell?
I doubt it, but the parallel of Walter having (creating? experimenting on?) Peter, and Bell having (creating? experimenting on?) Olivia would be interesting to say the least.
If Altlivia's mother is Marylin Dunham, would Olivia's mother not also be (Blue) Marylin by default?
Leap of Faith
I believe both Olivias have naturally blonde hair.
Alt!livia dyes it red. We know she dyes it because she has a box of dye on hand in Over There. Also, her hair color is different in this timeline. Perhaps because in the time between her being locked up in 6:02 and Neither Here Nor There she didn't have a chance to try that new color she would have. Or perhaps her pregnancy kept her from picking up a different color (many pregnant woman choose to avoid hair coloring).
Olivia I believe has her hair highlighted. We never see it happen, and we know she's a blonde as a child. It's rare for women with the shade of blonde of Subject 13's Olivia to maintain that lightness at ~30 without highlights.
The choice for one Olivia to choose new, bolder hair colors while the other seeks to maintain the length and color of her youth adds to the characterization of both Olivias, no?
In other words, they probably have the same natural hair color. But their differences lead them making different styling choices. No reason to question Marilyn's mothership of Alt!livia based on hair color.